How to avoid carbon buildup in an outboard?

[BillP]

Re: How to avoid carbon buildup in an outboard?

Many moons ago one of the posters (Kenny?) here was an omc tech. He wrote that his customers who ran treatment in every tank eventually had their rubber parts fail. Personally, I don't like the idea of running a solvent full time in my motors and haven't tried it. I run regular TCW03 and decarbonize every season or two by dunking it in the carbs and shutting down for 15 minutes. OMC Tuner in the past and Seafoam now. Either way, it takes a lot of running hrs (more than most would do in a season - even in Florida) to build up damaging carbon, even on a dirty, worn, cold running engines.

 

[jauguston]

Re: How to avoid carbon buildup in an outboard?

I have had good luck using Opti-2 mixed at 100-1 in all my premixed fuel two stroke engines from outboards to chain saws. No carbon build up and no smoke. The company is local here and have had their oil used in all two stroke engines from two large construction equipment rental yards for the last ten years without a single oil relate engine failure.

Jim

 

[JimS123]

Re: How to avoid carbon buildup in an outboard?

My 1984 9.9 Evinrude kicker has about 600 running hours - about 99% at idle at 2.1 mph trolling for Muskies and salmon. Its on a 19' bowrider. Its used every year and after 27 years the motor has had only 2 parts replaced - the sparkplugs. (OK, I know i should replace the impeller but it pumps water so good and I can see the telltale when I'm fishing so if it ever slows down I'll replace it----topic for another discussion).

Anywayyyyy, the first 2 years I had a lot of issues with plugs fouling. We typically troll for 3-4 hours at a time. Half way thru I pull in the lines and run at wot for a minute or 2, then resume fishing.

The third year, after consulting with an OMC factory R&D Tech, I replaced the plugs with Splitfires. Problem solved. No more smoke and no more fouling - ever. I run regular OMC TCW-3, E-10 gas and use a "sailboat prop", so even though she only runs 2.1 mph, the rpms are a tad higher than with the std prop.

I know I'll get blasted for the Splitfires. After this experience I tried them on my car, lawnmower, I'O engine and never saw a difference. But on the Rude they are the answer to a maiden's prayer!

 

[ondarvr]

Re: How to avoid carbon buildup in an outboard?

The Splitfires are probably hotter than the Champions, resulting in less fouling. Champion makes a huge selection of plugs, splitfire doesn't, this means a single plug needs to cover a broader range of motors and applications. The plug you have in it may be at the hot end of the range that will work for your motor.

 

[M9.9]

Re: How to avoid carbon buildup in an outboard?

Dunno if my theory is correct or not but when I run the engine w/out the line on to drain the engine fuel system of gas, once it gives that first little murmer (running out of fuel), I quickly spray the carb air intakes w/WD40 until it smokes out.
I realize the plugs are coated too so I clean them before the next launch.

The reason I do this, including winter storage prep, is that just allowing a two-stroke to run dry only, also burns off the lubrication in the gas. This method has always worked well for my engines.

I also use wd40 to lube through the fuel line and into the diaphram and d-valve areas as well as the cyclinder heads via plug ports, then manually pull the start cord two-three times.
In spring when I did the re&re on the diaphram is was coated and did not dry out over winter, same w/bottom of fuel bowl--no goo.

 

[pecheux]

Re: How to avoid carbon buildup in an outboard?

one very important thing ( when you mix the oil into the gas) is also to use the correct mixture ratio without adding own margins to the manufacturer margins. i have a 2000 yamaha 5 hp as a kicker and run it at recommended 100:1 and never had carbon buildup or any other motor problems.

oil is also not unimportant - i switched over at my 150 ficht ram from xd30 to xd50 and was stunned about the results. absolutely smoke free operation and a perfect clean exhaust hub where using the xd30 carbon buildup at the hub was visible.

I can be corrected if I am wrong but I suspect that xd30 is petroleum base oil while xd50 would be synthetic which would explain your results.